Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 240357

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1157 PM EDT Fri Mar 23 2018


High pressure anchored over northern Ontario will sustain northeast
flow across the area throughout the TAF period. This will generally
maintain a dry low level environment, supporting predominant VFR
conditions. Small window does exist Saturday morning for some degree
of MVFR stratus development given the prevailing cold flow off Lake
Huron. Greater inland penetration of this moisture will be limited
given the existing deep dry layer, but some potential remains mainly
at MBS late morning.  Any emerging stratus should progressively
scatter out under daytime mixing by afternoon.  Northeast winds
increasing to 10-15 kts during the daylight period.


* None


Issued at 404 PM EDT Fri Mar 23 2018


Combination of high amplitude midlevel ridge from the central Plains
northward through Canada and well defined upper level confluence
will lead to surface high pressure over the the Great Lakes this
weekend. Deep, persistent anticyclonic flow lower column cold air
advection, promoting very stable conditions from approximately 2.5
to 20 kft agl over southeastern Michigan. Impressive stability and
amount of dry air as RAP soundings suggesting that PWATs will be as
low as 0.07 inch by Saturday evening. Omega blocking will take root
throughout the weekend with geopotential heights ballooning to the
northeast through Hudson Bay. This will actually cause some
retrograding of the surface ridge back into the state to close out
the weekend.

Low impact weather for Saturday as tight area of deformation will
remain south of Southeast Michigan. This will keep the low track and
precipitation over southern Indiana. Good bet for high cloud veil to
extend northward south of I 96 corridor, but uncertainty exists on
opacity of the cloud. Solid northeast flow directly into the state
will lead to little movement on temperatures. Highs will range in
the lower 40s for much of the area, lower 30s in the Thumb.

Surface and midlevel ridge axes will remain back in place over
Michigan Sunday. Cold anomaly is shown to advect into eastern
portions of the area while undergoing heavy modification. Despite
what should be again full insolation, temperatures will likely be a
few degrees colder particularly for the far eastern areas. Highs
Sunday will be in the 30s to near 40 degrees.

High pressure departing eastward on Monday will maintain one final
day of dry conditions. Meanwhile, an upper level ridge axis crossing
the region will bring increasing southerly flow through the day
allowing highs to make a run for the low 50s. A string of
disturbances ejecting out of a longwave trough over the Western US
along with increasing moisture under deep southerly flow will bring
the next chance of widespread rainfall to the region early Tuesday
through early Wednesday. A frontal boundary crossing the region
Wednesday will then end rainfall as a push of slightly drier air
arrives late Wednesday. Mild conditions look to continue through
midweek with highs in the low to mid 50s. Will then need to monitor
the potential for another round of precipitation late next week as a
southern stream wave ejects out of the Southwest US while a northern
stream wave brings a push of colder air to the region.


Strong high pressure over James Bay tonight will maintain northeast
winds of 15 to 25 knots over Lake Huron right through Saturday
night, with winds just modestly decreasing on Sunday. Elevated waves
in excess of 4 feet will persist over much of southern Lake Huron,
and small craft advisories remain in effect.

High pressure reaching the East Coast early next week will allow
winds to shift to the southeast and increase, with gusts approaching
gale force over the open waters of Lake huron as a frontal boundary
moves through during the mid week period.


Lake Huron...Small Craft Advisory until noon EDT Sunday for LHZ421-441>443.

     Small Craft Advisory from 8 AM Saturday to noon EDT Sunday for

Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.



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